Set the entry for the removed memory to 0. If the entry related meory is not whole removed, split it to smaller page, and clear it.
CC: David Rientjes <[email protected]> CC: Jiang Liu <[email protected]> CC: Len Brown <[email protected]> CC: Benjamin Herrenschmidt <[email protected]> CC: Paul Mackerras <[email protected]> CC: Christoph Lameter <[email protected]> Cc: Minchan Kim <[email protected]> CC: Andrew Morton <[email protected]> CC: KOSAKI Motohiro <[email protected]> CC: Yasuaki Ishimatsu <[email protected]> Signed-off-by: Wen Congyang <[email protected]> --- arch/x86/mm/init_64.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 156 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 78b94bc..d78f352 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -675,11 +675,164 @@ int arch_add_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(arch_add_memory); +static void __meminit +phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end) +{ + unsigned pages = 0; + int i = pte_index(addr); + + pte_t *pte = pte_page + pte_index(addr); + + for (; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE, pte++) { + + if (addr >= end) + break; + + if (!pte_present(*pte)) + continue; + + pages++; + set_pte(pte, __pte(0)); + } + + update_page_count(PG_LEVEL_4K, -pages); +} + +static void __meminit +phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pmd_index(addr); + + for (; i < PTRS_PER_PMD; i++, addr = next) { + unsigned long pte_phys; + pmd_t *pmd = pmd_page + pmd_index(addr); + pte_t *pte; + + if (addr >= end) + break; + + next = (addr & PMD_MASK) + PMD_SIZE; + + if (!pmd_present(*pmd)) + continue; + + if (pmd_large(*pmd)) { + if ((addr & ~PMD_MASK) == 0 && next <= end) { + set_pmd(pmd, __pmd(0)); + pages++; + continue; + } + + /* + * We use 2M page, but we need to remove part of them, + * so split 2M page to 4K page. + */ + pte = alloc_low_page(&pte_phys); + __split_large_page((pte_t *)pmd, addr, pte); + + spin_lock(&init_mm.page_table_lock); + pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + spin_lock(&init_mm.page_table_lock); + pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd)); + phys_pte_remove(pte, addr, end); + unmap_low_page(pte); + spin_unlock(&init_mm.page_table_lock); + } + update_page_count(PG_LEVEL_2M, -pages); +} + +static void __meminit +phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pud_index(addr); + + for (; i < PTRS_PER_PUD; i++, addr = next) { + unsigned long pmd_phys; + pud_t *pud = pud_page + pud_index(addr); + pmd_t *pmd; + + if (addr >= end) + break; + + next = (addr & PUD_MASK) + PUD_SIZE; + + if (!pud_present(*pud)) + continue; + + if (pud_large(*pud)) { + if ((addr & ~PUD_MASK) == 0 && next <= end) { + set_pud(pud, __pud(0)); + pages++; + continue; + } + + /* + * We use 1G page, but we need to remove part of them, + * so split 1G page to 2M page. + */ + pmd = alloc_low_page(&pmd_phys); + __split_large_page((pte_t *)pud, addr, (pte_t *)pmd); + + spin_lock(&init_mm.page_table_lock); + pud_populate(&init_mm, pud, __va(pmd_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + pmd = map_low_page(pmd_offset(pud, 0)); + phys_pmd_remove(pmd, addr, end); + unmap_low_page(pmd); + __flush_tlb_all(); + } + __flush_tlb_all(); + + update_page_count(PG_LEVEL_1G, -pages); +} + +void __meminit +kernel_physical_mapping_remove(unsigned long start, unsigned long end) +{ + unsigned long next; + + start = (unsigned long)__va(start); + end = (unsigned long)__va(end); + + for (; start < end; start = next) { + pgd_t *pgd = pgd_offset_k(start); + pud_t *pud; + + next = (start + PGDIR_SIZE) & PGDIR_MASK; + if (next > end) + next = end; + + if (!pgd_present(*pgd)) + continue; + + pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); + phys_pud_remove(pud, __pa(start), __pa(end)); + unmap_low_page(pud); + } + + __flush_tlb_all(); +} + #ifdef CONFIG_MEMORY_HOTREMOVE -int arch_remove_memory(unsigned long start, unsigned long size) +int __ref arch_remove_memory(unsigned long start, unsigned long size) { - /* TODO */ - return -EBUSY; + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + int ret; + + ret = __remove_pages(start_pfn, nr_pages); + WARN_ON_ONCE(ret); + + kernel_physical_mapping_remove(start, start + size); + + return ret; } #endif #endif /* CONFIG_MEMORY_HOTPLUG */ -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
